Glucocorticoids (cortisol for human) act as an important role in the maintenance of glucose homeostasis and metabolism of lipid and protein in the body. Particularly, excessive glucocorticoids in the liver and adipose tissues cause metabolic syndromes, such as, insulin resistances, visceral obesity, hypertension, and dyslipidemia.
It has been known that 11β-hydroxysteroid dehydrogenase (11β-HSD) has two kinds of isozymes, type 1 and type 2. First, 11β-HSD1 is an NADPH-dependent reductase, and an important enzyme for converting inactive glucocorticoid, cortisone, into active glucocorticoid, cortisol, in the liver, adiopose, and brain tissues. 11β-HSD2 performs an action contrary to 11β-HSD1 in an NAD-dependent manner, and is expressed mainly in the kidney.
It was reported that 11β-HSD1-overexpressed transgenic mice had a normal cortisol level in the blood, but had an increased cortisol level in the adiopose, which caused insulin resistances, visceral obesity, hyperlipidemia, and hypertension, and that they showed a larger increase in body weight and a larger increase rate in body weight than a non-transgenic mouse group [Masuzaki H. Science 2001, 294, 2166-2170; Masuzaki H. J. Clin. Invest. 2003, 112, 83-90]. In addition, it was reported that 11β-HSD1 knowout mice showed an improvement in glucose tolerance, a deterioration in blood triglycerides, and an increase in HDL-cholesterol [Morton N. M. J. Biol. Chem. 2001, 276, 41293-41300].
Carbenoxolone (CBX), which is a nonselective inhibitor of 11β-HSD1, improves insulin sensitivity of healthy candidates and type 2 diabetic patients, but not the obese [Andrew, R. C. J. Clin. Endocrionl. Metab. 2003, 88, 285-291]. However, the CBX was reported to cause hypopotassemia and hypertension due to nonselective inhibition for 11β-HSD1 and 11β-HSD2, and thus the development thereof is limited to therapeutic agents [Kotelevtsev, Y. J. Clin. Invest. 1999, 103, 683-689].
Therefore, the effective and selective inhibitors of 11β-HSD1 enzymes inhibit the conversion of glucocorticoids into the active type to suppress the action of glucocorticoids in the tissue, and as a result, they can be used as therapeutic agents for metabolic syndromes caused by glucocorticoids, such as non-insulin dependent type 2 diabetes, obesity, hyperlipidemia, hypertension, glucose tolerance, and the like.
For this reason, the present inventors searched compounds having effective and selective inhibitory activity for 11β-HSD1 enzymes for the purpose of regulating or treating metabolic syndromes such as obesity, diabetes, etc. As a result, they could synthesize novel picolinamide and pyrimidine-4-carboxamide compounds, and verify that these novel compounds exhibited effective and selective inhibitory activity for 11β-HSD1 enzymes.